Add truth inclusive kinematics to reconstruction

Included here @bschmookler

There is a related MR, !81 (merged), that calculates DIS x and Q2 from the reconstructed particles. Ultimately I think that MR will be made large obsolete by including the electron kinematics in juggler and in the reconstruction as well.

benchmarks/dvcs/analysis/dvcs_ps_gen.cxx

+#include "TH2F.h"
+#include "TLorentzVector.h"
+#include "TGenPhaseSpace.h"
+
+#include <iostream>
+
 void dvcs_ps_gen() {
   double E_p = 100.0;
   double M_p = 0.938;